METAL-ASSISTED REACTIONS-13. RAPID, SELECTIVE REDUCTIVE CLEAVAGE OF PHENOLIC HYDROXYL GROUPS BY CATALYTIC TRANSFER METHODS

Article abstract of DOI:10.1016/0040-4020(82)80091-4

Previous work has shown that, after converting phenols into suitable phenolic ethers, the aromatic C-O bond of the original phenol can be reductively cleaved heterogeneously to give a C-H bond through the use of molecular hydrogen or hydrogen donors together with a transition metal catalyst.The present work provides a method for selectively replacing a phenolic OH group by H in just a few minutes, compared with the 2 to 4 hr required previously using a hydrogen donor and the several hours under pressure required for molecular hydrogen.Various kinds of groups are suitable for preparing the required phenolic ethers from phenols, but the best ones are strongly electronwithdrawing heteroaromatic entities.Solvent appears to play an important role in this heterogeneous reaction, the mechanism of which is discussed.